Wash and wrap all raw mangoes in aluminium foil individually. Roast at 180 degrees Celsius for 30 minutes. Remove from oven and let them cool down.(You can alternatively boil the raw mangoes till soft).
Remove foil and peel the mangoes and collect the pulp in a bowl.
In a blender jar combine raw mango pulp, roasted cumin, black pepper powder, red chilli powder, black salt, jaggery /sugar, mint leaves and salt. You may add ice cubes also if required.
Blend for one minute and add chilled water as required. Blend again and pour into glasses and garnish with mint sprig.